Solid-state light emitters, such as light-emitting diodes (LEDs) and laser diodes, have several advantages over using more traditional arc lamps during curing processes, such as ultraviolet (UV) curing processes. Solid-state light emitters generally use less power, generate less heat, produce a higher quality cure, and have higher reliability than the traditional arc lamps. Some modifications increase the effectiveness and efficiency of the solid-state light emitters even further. Conventional lighting modules employing solid-state light emitters have a housing within which light-emitting elements, such as LEDs and laser diodes, are positioned. Light is irradiated from the solid-state light emitters through a flat front window of the housing onto a substrate, for example, to cure a light-activated material on the surface of the substrate.
The inventors herein have recognized potential issues with the above approach. Solid-state light emitters such as LED's, and other types of lighting modules may be characterized as exhibiting a Lambertian or near-Lambertian emission pattern. Accordingly, one challenge with lighting modules employing solid-state light emitters is providing a uniform irradiance of light across an entire target object or surface. In particular, curing of large two-dimensional surfaces may require manufacture of large lighting modules that are costly and cumbersome, or may require combining multiple lighting modules to provide irradiance over the target surface area. Namely, irradiance uniformity is poor near edges of emission patterns of individual lighting modules and at junctions between multiple lighting modules. Furthermore, irradiating light from lighting modules through flat front windows, wherein light is emitted from an array of light-emitting elements only through a front plane of the lighting module, can further contribute to poor irradiance uniformity near the edges of the lighting module. Non-uniformities in irradiance can result in curing non-uniformities over a substrate surface, and can thereby reduce the efficiency of the curing process.
One approach that at least partially addresses the aforementioned issues includes a lighting module, comprising a window casing, a window mounted at a window casing front face, wherein a window front face spans a length of the window casing front face, and the window front face is flush with the window casing front face, and an array of light-emitting elements positioned behind the window casing to emit light through the window.
In another embodiment, a method of irradiating light may include irradiating light from an array of lighting modules, each of the lighting modules comprising a window casing, a window mounted at a window casing front side, wherein the window comprises a window front face spanning a front plane length of the window casing front side, and wherein the window front face is flush and parallel with the window casing front side, first and second window sidewalls extending rearwards from left and right edges of the window front face, respectively, and an array of light-emitting elements positioned within the window casing to emit light through the window front plane and through the first and second window sidewalls.
In another embodiment, a lighting system may include a power supply, a cooling subsystem, a light-emitting subsystem comprising a window casing, a window frame mounted at a window casing front side, a window mounted at a front plane of the window frame, the window comprising a window front face spanning a front plane length, wherein the window front face is flush with a window frame front side, and first and second window sidewalls extending rearwards from first and second edges of the window front face at first and second angles, respectively, a linear array of light-emitting elements within the window casing, the linear array aligned with and emitting light through a window front plane and through the first and second window sidewalls, wherein window sidewalls at the first and second edges of the window front face are aligned flush with window casing sidewalls, the window sidewalls extending perpendicularly back from the front plane, the linear array of light-emitting elements comprises a middle portion in between two end portions, and a controller, including instructions executable to supply a first, larger, drive current to each of a plurality of light-emitting elements in the middle portion, and supply a second, smaller, drive current to each of a plurality of light-emitting elements in the two end portions.
It will be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.